Stellar Questions: Gravitational Waves, Time Travel & the Search for Extraterrestrial Life |...

[00:00:00] Welcome back to another fun and exciting Q&A episode of Space Nuts. 15 seconds. Guidance is internal. 10, 9. Ignition sequence start. Space Nuts. 5, 4, 3, 2. 1, 2, 3, 4, 5, 5, 4, 3, 2, 1. Space Nuts. Astronauts report it feels good. I'm your host for this episode, Heidi Campo, and joining us is Professor Fred Watson.

[00:00:28] I don't know why I've done that twice now, I've mispronounced your name. Astronomer at large. Fred, how are you? Well, thank you. I don't really care how the name's pronounced. Fred's pretty straightforward. You know, when I go to Scandinavia, I've probably said this before, Heidi, there are Freds. I see Fred everywhere because it's the Scandinavian word meaning peace. Oh.

[00:00:53] And so Fred Garten is a peace street and I've got lots of photographs standing underneath peace streets because they're called Fred. That's lovely. I love that. There you go. I guess my name is a German name, it's short for Adelheid, and it means noble. Indeed it is. There you go. So mine's German as well. It's from Fried. It's the same word, yeah.

[00:01:19] Well, our first question from today is from Peter. I'm wondering if, I don't think I know the history of that one. I think it's European. It's very old. It goes back to biblical times. Yeah. It's the rock. Peter is the rock, Petra. That's what it means is the rock. Yeah. I like that. Let's see if we can figure out the etymology of all the names today. I think we've probably run out now.

[00:01:46] All right. So yeah, our first question is from Peter and he says, Hi, Space Nuts. Queen's great 1975 album, A Night at the Opera, has a song called 39, written by astrophysicist Brian May, of course. In the song, a band of intrepid volunteers leave Earth in a spaceship to find another planet for human habitation. They leave in the year 39, we don't know what century,

[00:02:13] but they have been in the year 39, and their trip takes one year. They must have had a good warp drive, because when they return, it is the year 39 in the next century. So they have been away for 100 years in Earth time. The protagonist of the song laments his remaining life with his wife and children dead, and just his great granddaughter remaining, now a very old lady. My question is these. My questions are these. Approximately how far out into the galaxy might

[00:02:42] they have gone in that time, and what would their average speed have been? At first I thought that they only traveled for a year, and the near star is more than four light years away. So it is a wasted trip. But then they were away from the Earth for 100 years, so maybe they checked out many stars with planetary systems. Now I'm just confused. And that's our question from Peter.

[00:03:08] Peter Well, so it turns out that it's reasonably easy to do the calculation that Peter's interested in. Because what he's talking about is something we call time dilation. It comes from, in this case, it comes from Einstein's special theory of relativity that covers the effects of things that are moving

[00:03:33] close to the speed of light. And so you've got to be moving close to the speed of light to experience this. So what we've got here is a fraction of 100. It's been a year on Earth. Sorry, it's been a year for the travelers, but it's been 100 years on Earth. So that means that the time dilation effect is 100. It's 100 times.

[00:04:00] Now there's a formula for time dilation which is reasonably simple. I'll just quote it since I learned it in relativity 100 years ago. The time dilation is, and it's a fraction, it's one over the square root of one minus v squared over c squared, where v is the velocity that you're traveling at and c is the

[00:04:22] velocity of light. So it's a relatively straightforward formula. And so yesterday what I did was I put the numbers into it to work out what speed they would have to travel for that ratio of 100 years on Earth to one year on the spacecraft. And it turns out to me, here's my calculation there, you probably can't see it. Oh, by hand. Oh my goodness, Fred. Back of an envelope.

[00:04:48] Back before everyone outsourced their brains to Chad GPT. That is handwritten math, everybody. And the bottom line, you probably can't see it. They would have to travel at 99.995% of the speed of light. So 99.995% of the speed of light. If you travel for a year, then on Earth, you've got 100 years elapsed. Now that probably means that they went out for 50 light years and then came back again.

[00:05:18] So they could have visited many stellar systems in that time, although they wouldn't have seen much of it going past them at 99.995% of the speed of light. So yeah, that's the answer. Check it out. You can look up time dilation on the web and you'll find all the formulae there. And that's the easy, you know, it's a relatively easy question to answer. So Peter, thank you for getting my brain working on these

[00:05:47] questions again, because I appreciate that. And I've always thought it was a good thing to have at the back of your mind, the relativistic time dilation. Travel near the speed of light, just in case you ever find yourself doing that. Fred, I am tickled at the amount of times you said easy and time dilation equation in that answer. I think you use the word, this is easy or the phrase, this is easy at least

[00:06:13] two or maybe three times. So that's just, I don't know if I need to work on my math skills or if you're just that brilliant, but that was, that's adorable. It's not, it's a lot easier than some of the ones I used to stumble over back when I was, I, there's a, this must not go beyond these four walls, Heidi, but there's a math exam at university that I failed five times. It took me six attempts to pass it. Oh my goodness. So there's hope for the rest of us.

[00:06:42] Yeah. Oh gosh. Yeah. I still shudder at that. It was the wrong kind of mathematics. You had to do it. It was pure mathematics and it, my brain just didn't work that way. Yeah. Mine does not either. Space nuts. Um, well our next question is from Trent and this is an audio question that we're going to queue up and we're going to play for you right now.

[00:07:13] Hello, Heidi and Professor Watson. My name is Trent. I'm from North Georgia. USA. And I had a question in reference to Ben's question from Northwestern University in episode 530. I was wondering how an observatory could view something that's already happened.

[00:07:41] For example, in his question he asked about an observatory turning to look at source of gravitational wave. And I was thinking, as gravitational waves move at the speed of light and the light from that source is also moving at the speed of light. After the gravitational wave observatory has already observed the phenomenon,

[00:08:08] how can a radio observatory or a light observatory observe the same phenomena since the other waves would have already passed us? So, hope this question piqued your interest. I would love to hear the answer. And you all have a wonderful time. I love your show. Never miss an episode. Y'all are fantastic. Bye-bye.

[00:08:36] That was sweet. Thank you so much, Trent. That, uh, that was wonderful. So, Trent's question is a great one. Um, and his point is absolutely well made. You know, that the, if you've got a phenomenon that causes gravitational waves and also beams out light, uh, then the two travel at the same speed. So how can a detection in gravitational waves, uh, then be used to, you know,

[00:09:03] somebody phones up an observatory and says, oh, we've seen these gravitational waves. Can you point your telescope in this direction? What are you going to see? Uh, the, the, I guess, uh, Trent's hypothesis is that it will be nothing, but it's not quite that straightforward, uh, because often, um, the, the counterpart of an event seen at one in, in one way, for example, by gravitational waves,

[00:09:31] the counterpart, um, in the visible light spectrum, for example, or the radio spectrum, um, whilst the radiation travels at the same speed, um, there are sometimes delays because you've got different mechanisms that give rise to that, uh, signal with the, what you might call the follow-up radiation. I'm thinking mostly, uh, uh, perhaps the best example of this, uh, is in what we call gamma ray

[00:10:01] bursts, uh, which were discovered back in the seventies by spacecraft, which were put into orbit to look for, uh, people breaking atmospheric nuclear test bands. Um, the idea was to, to detect gamma rays from illicit nuclear test bands that might be going on on the earth's surface in the atmosphere, uh, because they were banned, uh, but people wanted to police that. And so these spacecraft were developed and put into

[00:10:31] orbit and they didn't find any illicit nuclear tests. What they found was these phenomena in deep space, we call gamma ray bursts, which are caused, we think by cataclysmic events, uh, on, uh, in, in, principally in distant galaxies. Now, some, um, what you really want to find as well as the gamma rays is whether there's another, uh, you know, another frequency or something that's carrying information.

[00:10:57] And so it was what we call the optical counterparts of those bursts that people were looking for. And by that, I mean, the visible light flash. And to do that, you would want to first of all detect the gamma ray burst and then alert visible light telescopes to the direction that that had come from so that they could home in on the, the target as quickly as possible after the event

[00:11:22] to try and work out what these things were. Because if you've got information from gamma rays and information from visible light, then you, you've got a chance of working it out. And indeed that's the case because the visible light flash is, uh, it's usually caused by whatever caused the gamma rays interacting with the environment that's around it. And that means rarefied gas usually. And it's the effect

[00:11:50] of that rarefied gas, perhaps by a shockwave moving through it that gives you the visible light flash. And that's going to be after the original gamma ray burst itself. Gamma ray bursts last a few seconds. They're sort of second long, uh, a bit different from the, the, my, my mini, millisecond, uh, fast radio bursts that we also see. So all these phenomena, um, have different counterpart,

[00:12:15] different components to them. And, uh, it, you're not trying to see back in time when you're following up the, you know, the target of opportunity observations, which is what we were talking about, uh, previously, uh, you're actually just looking at a different aspect of whatever that cataclysmic event has been. I don't know whether that's a satisfactory explanation, but that's what's happening. So you chase it up as quickly as you can to try and learn as much as you can.

[00:12:45] Dr. Thank you so much, Trent. Our next question is from Chris and Chris says, thank you for the podcast folks. Good stuff. Indeed. On earth, living organisms can sense a small part of the EM spectrum from infrared through visible light up to the ultraviolet. But as far as we know, no organism can detect lower or higher frequencies such as radio or x-rays on earth. This

[00:13:13] could be because such senses don't convey usefulness, but elsewhere it could. So is there any limiting factor in biology, chemistry, or physics that prevents organisms detecting this different, this different parts of the spectrum spectrum and therefore possibly communicating with each other like this? Could extraterrestrial life use radio to communicate with each other?

[00:13:40] Isn't that a great question, Heidi? Because yeah, it's thinking outside the box and I like that very much. You might have a comment on that actually, because science fiction looks at these things quite a lot. You know, I'm such a science fiction nerd. Well, I'm just thinking of our episode a few weeks ago about the whale bubbles. Yeah, yep, that's right. The whale bubbles might well be a way of communicating,

[00:14:05] although of course you're using visible light there. And I think that's a little bit different from the sort of thing that Chris is thinking of. So it's not quite true that we're not sensitive to some of these other electromagnetic radiations, because for example, x-rays can damage tissue. And so in a sense,

[00:14:31] what you've got there is a detector, albeit it's the wrong kind of, you don't really want your tissue to be damaged, but that is an organism being able to detect a high frequency radiation, such as x-rays, gamma rays too. So that's all what we call ionizing radiation, it's damaging radiation. And biological organisms can

[00:14:57] detect that, but it's usually in a very destructive way. There have been many experiments done and tests done to see whether the radiation emitted by mobile phones has a damaging effect on people's well-being. And the evidence that I've read is that no, the radiation levels are too low

[00:15:24] to have any kind of effect. But I think higher, you know, higher intensities, and I'm thinking now of microwaves. Your microwave oven is cooking by means of radiation that causes things to get hot. And if you flood your brain with that, it's going to get hot. And in fact, and it was Andrew Dunkley who told me this because I didn't know, the way your microwave does four or five beeps at the end of every cooking

[00:15:54] session when it reaches the prescribed time is not just for fancy music, it's to give you a few seconds for the microwaves inside it to settle down before you open the door. Oh my goodness. And irradiate yourself with microwaves. So I always thought I was terribly clever because I always would try and time it. So I open the door right before the beeps go off. So I've just been cooking myself with radiation every time

[00:16:23] I did that. Yeah. So I think the bottom line here is that it is possible to imagine that there could be ways in which, you know, extraterrestrial species might be able to communicate by using these different electromagnetic frequencies in a way that we haven't thought of. And that's, I suppose, one of the other

[00:16:49] things that leads us to that movie that both you and I have raved about, Arrival. Yeah. That, you know, you're looking for, you've got to think outside the box as to what you might, how you might communicate with extraterrestrial organisms and whales too. I think blowing bubble rings is a great way of thinking outside the box or outside the ring.

[00:17:15] Well, I mean, just communication is so interesting in general. I don't know the exact percentage. I want to say it's somewhere in the eighties, but we'll just say for discussion sake that 80% of our communication is nonverbal. I have a patient that I work with who had a TBI and he can't talk, but he says so much. I work as a graduate assistant research coordinator at university. And I'm always telling

[00:17:43] all the new students who are coming in and working with him, I'm like, he says a lot. You just have to learn to listen better because he communicates with you like you wouldn't believe. We can have full conversations with just the movements of his eyebrows and his expressions and gestures. And it's really amazing. So I like this about communication and who knows, maybe there's some rock creatures out there that their shells are thick enough that radio frequencies would be good. What was that movie

[00:18:12] about the military kids who go to space? Gosh, it's a little bit of an older one. I can't think of the title right now where they're fighting the bugs in space. Okay. Okay. I got, I so seldom watch science fiction movies. No use to you whatsoever. It was kind of a funny one. You're okay and I feel fine. Space nuts.

[00:18:38] Yeah. Well, I guess that brings us to our last question from Martin. And this one is also an audio question. So I'm going to go ahead and queue up that last audio question for Martin now. Hello, Space Nuts. Martin Berman Gorvine here, writer extraordinaire in many genres,

[00:19:02] uh, with a, uh, question, um, that I know I've tried to ask, uh, before and somehow it hasn't ever quite gotten through. Um, and it's inspired again by your discussion of Titan in the latest episode that

[00:19:21] I'm listening to, um, is there any reason to rule out, um, the existence of moons with roughly the mass of the earth orbiting, um, gas giants? And we know some of those are quite a bit larger than Jupiter,

[00:19:48] um, in other solar systems. And if you could have an earth mass moon, um, is there again, in principle, any reason to think you could not have a, an earth like environment, um, where life could evolve? Uh, can't wait for the answer.

[00:20:16] Yeah. And thanks for doing such a great job, including Heidi Campo who is marvelous. Um, when she comes in instead of Andrew though, nobody can replace our Andrew Martin Berman Gorvine over and out, out, out, out, out. There you go. Oh, Martin, that was so sweet. We appreciate that so much. And

[00:20:44] it's true. Nobody can replace Andrew. And, uh, I, I know I probably have been really not doing my job with the dad jokes, but I, I think I've got my own brand of the sci-fi. By the way, that movie was called Starship Troopers. I had to just look it up because it was driving me nuts. It's a kind of a commentary on communism. Um, but yeah, great question, Martin. Let's let Fred take it away.

[00:21:08] Yes, as they always are. Um, and, um, yeah, thanks, Martin. Thanks for sticking in there with the question that we might've overlooked at some time in the past. I don't know how we managed that because it's a good question. And so I was thinking about this too, and I don't think there is any reason why you shouldn't have, be able to have an earth sized, uh, moon or satellite of a large gas giant.

[00:21:38] Um, because, and, and in some ways you'd, you'd think it would be natural to do that. We, we see, um, what we call super Jupiters, uh, planets around other stars, exoplanets, which are bigger than Jupiter, not that much bigger because if you go up to 13 times the mass of Jupiter, it's not a planet anymore. It becomes a brown dwarf star because you've got, um, reactions that can take place,

[00:22:04] low level nuclear reactions that can take place and mean that it radiates in the infrared. There, Jupiter itself radiates in the infrared too. It's got these low level reactions, but it's not big enough to be a brown dwarf star. But if you had, you know, something with twice the massive Jupiter, um, there's no reason why, as far as I can see, and I'm not, I'm not a planetary scientist per se,

[00:22:30] but I do hang out with them. So I know the sort of things that they, they think about. Um, I don't think there's any reason why you shouldn't actually manage to generate a rocky, a large rocky planet, uh, sorry, a large rocky moon, which was planet sized from, uh, from the same part of the swirling, uh, disk of gas and dust from which planets are formed.

[00:22:56] Some of my colleagues might correct me on that, but I don't think there is a limit. And in that regard, I don't think there's a limit as to whether, uh, such a planet or such a moon might actually be habitable. Um, the, the only thing is we, that most of these, most of these large Jupiters that we find in, in other solar systems are very close to their parent star. And so, um, if you imagine, uh, you know, you've got a planet that goes around its parent star

[00:23:25] in just a few days, the moon would have to go around its parent planet, um, quicker than that, or else all sorts of dynamic interactions would take place and it would probably lose its moon. But, um, then, so then you've got this phenomenon where, uh, you've got something very hot, uh, whose temperature is changing very rapidly as it orbits, uh, its parent planet.

[00:23:50] So I suspect, um, that it might not be the kind of ideal world, uh, for life to evolve, uh, because of these perhaps rapid changes of temperature. Now, Martin being a writer in many genres is usually looking for story, for ideas, for science fiction stories. And this might be one that, you know, maybe in a year or two's time, we might read about species on the planet, on a moon, the size of the

[00:24:19] Earth, going around the hot Jupiter somewhere deep in the solar system with a new, a new and completely different kind of life form that uses radio for communications. So that would, uh, would solve all our issues, wouldn't it? Well, the best writers, I think they, the best science fiction writers use fringe science. And I, um, I'm going to butcher his last name. I always do. Michael Crichton. Oh yes. Yep. Jurassic Park. I always wanted to see,

[00:24:47] so I said it right. Okay. Thank goodness. I usually say Crichton and people are like, it's Creighton. Um, yeah. Yeah. I mean, he did an amazing job of writing books that were just right on the fringe of, of possible. And that's, uh, that's always so fun to think of. Well, as Martin does as well, I think. Yeah. I'm going to have to look up some of Martin's books. It sounds like they're right up my alley and probably a lot of our other, um, listeners too. Yeah, that's right. But a great question, Martin. And thank you. And I hope

[00:25:17] I've given you the right answer. I'll check next time I talk to some of my planetary specialists as to whether I've overstepped the mark. Well, Fred, this has been so much fun. I always have a great time, uh, with these Q and A episodes. It's so fun to hear how just so smart people are asking great questions. Indeed they are. And, um, they're challenging too sometimes. Yeah. Keep them coming guys. These questions are really, really fun. It's good when you get a mix of

[00:25:47] questions that aren't just black hole questions. That's right. Yes. All right. Well, uh, this, this concludes today's episode and we hope to see you guys, uh, back here next time for another regular, regular episode and then Q and A episodes and on and on for eternity. How about that, Fred? Or as, or as long as we can do it for. Ah, that works too. Thank you so much,

[00:26:13] everybody. We'll catch you next time. Hi, Fred. Hi, Heidi. Hello, Hugh in the studio. Andrew reporting from the Crown Princess cruise ship. We are currently rounding the Cape of Good Hope, which was also once known as the Cape of Storms. And that's actually what it's been like. Last time I spoke to you, we'd been to Mauritius. Unfortunately, we could not get to Cape Town on the

[00:26:40] other side of Africa in time, uh, because of the storms. So we just hung around Durban for a while, going backwards and forwards. And then finally they arranged for us to go ashore in Durban. So we did that. And Judy and I did a tour out to the place where Nelson Mandela was captured in 1962 and arrested. And they've got this fantastic sculpture there, uh, of Nelson Mandela's, um,

[00:27:07] head face. Uh, it's, it's 50 metal poles that have been put in the ground and, and they just look like, you know, a bunch of poles sticking up out of nowhere. But when you stand on a specific spot, you can see his face. It is quite remarkable. And the museum there telling the life, uh, and times of, uh, the apartheid anti-apartheid movement, starting with, uh, Mahatma Gandhi and then, uh, the formation

[00:27:33] of the ANC, the African National Congress, and ultimately the leadership of, uh, of Nelson Mandela and him becoming president and wiping out apartheid. Fantastic place to visit if you ever get a chance. It's really remarkable. I was also struck by how the landscape around Durban, uh, is so much like home, uh, grasslands and eucalypt trees, and it just looks so much like Australia with taller mountains

[00:27:59] compared to where I live in Dubbo. Uh, but we're just working our way around the, um, the Horn of Africa, uh, due into Cape Town tomorrow morning. We'll spend a couple of days there and we're going on a, on a safari. So, uh, we're looking forward to that. Uh, it hasn't been too bad on board. The, the captain's, um, taking his time so we don't get caught up in heavy swells, but right now it's looking very angry outside and, uh, all the, uh, the decks have been closed. So we're inside

[00:28:29] staying nice and cool, uh, nice and warm. It's pretty cold out there and it looks like it'll be raining when we get to Cape Town. Uh, but because we're two days behind schedule as a consequence of the weather, we'll be missing out on a few ports. So we won't be going to, uh, any of the, uh, stops that we'd previously planned such as, uh, the Canary Islands, uh, Cape Verde. And we're also going to miss out on Gibraltar very sadly, but we're picking up Tenerife. So, um, we got Durban,

[00:28:59] we got Tenerife. We miss those other three and then, um, yeah, we'll move on from there. Hopefully, uh, get to Barcelona on time because there's a big change of, uh, of passengers there. So they can't be late for that. Otherwise people will be pitching tents. That's about it. I think, uh, we're having a great time feeling relaxed and, uh, hope all is well with everybody on the Space Nuts team and the audience around the wider world. If you, if you're anywhere where I'm stopping,

[00:29:27] maybe you can wave if you, if you close by, uh, but I'll talk to you again next week. Bye for now. Space Nuts. You'll be listening to the Space Nuts podcast. Available at Apple Podcasts, Spotify, iHeartRadio, or your favorite podcast player. You can also stream on demand at Bytes.com. This has been another quality podcast production from Bytes.com.